As an illustrative example, it may be desirable to perform injection on one or more wells to stimulate production from a subterranean formation, in particular, a hydrocarbon-bearing reservoir, to increase potential production therefrom. These injection operations may include providing an injection fluid to specific, or target, regions of the subterranean formation and may utilize stimulation ports within a casing string to provide the injection fluid from the casing conduit to the target region of the subterranean formation.
A major concern to well operators is injection failure in unconsolidated reservoirs, especially unsustained and reduced injectivity due to water quality and fines production. Constant injection of fluids having a high concentration of solids at a high flux rate over years may erode portions of the injector screens. Erosion from inside out may cause screen failure and expose tubing to formation during a backflow or a cross flow. Fines (sands) that are carried by formation fluids during a crossflow or a backflow event may fill tubing and cause a loss of injectivity, especially amongst co-mingled injectors targeting unconsolidated reservoirs. Additionally, occurrence of a water hammer event or a pressure surge within the string, such as during a shut-in, may exacerbate the risk of a sand failure.
There exists a need for injection methods and apparatus that are counteractive to the deleterious effect of backflows, crossflows and internal pressure surges on the service life of injection systems so as to prolong their useful service life.
Despite recent advances, there remains an unmet need in the art to optimize design of well-bore injection systems such that ingestion of formation fluids into the injector string due to flow reversals is abated, if not wholly avoided.